Slim piece of time

October 2013 - It’d be a stretch to say watches are enjoying a renaissance because they haven’t really gone out of style. From James Bond’s Omega Seamaster Planet Ocean to Samsung’s Wi-Fi enabled Galaxy Gear smartwatch, the levels to which manufacturers are taking their timepieces tells us that it’s not just about time.

“No one buys a Swiss watch to find out what time it is,” said a February article in The Economist.

One Chicago company has moved away from the trend of feature-packed watches by taking a minimal approach to design, focusing on nothing but time. Central Standard Timing developed the CST-01, a watch that isn’t much more than a flexible stainless steel band 0.8 millimeter thick, skinnier than a dime. At first glance, it could be a fashion accessory—a bracelet or bangle—but the clean look of stainless doesn’t assign it to men or women. The laminated display uses E Ink technology, the same text used by Amazon’s Kindle, tucked away inside the band. Its ultrathin battery charges in 15 minutes from an external dock with a charge lasting more than a month.

David Vondle and Jerry O’Leary, designer and electrical engineer, respectively, founded CST after working together at IDEO, a product design firm in Chicago. Stainless steel was an ideal option because of its compatibility with most people’s skin, Vondle says. The chromium oxide passivation layer that prevents stainless from rusting also protects skin from reacting to the small amount of nickel in the watch’s alloy. Stainless can also be PVD coated for different finishes or colors.

“The alloy in our prototype bands has about 8 percent nickel but behaves as less than 0.1 percent nickel as far as the wearer is concerned,” he says. “CST is also exploring titanium alloys for their bio-compatibility, low elastic modulus, and ability to be hot formed.”

Embedded time

The watch’s components are nestled inside a 0.5 millimeter pocket etched into the stainless spring steel metal band. CST investigated methods of creating a pocket for the electronics, which included looking into both multiple layers and stamping a pocket into the steel band. Ultimately, Vondle and O’Leary researched photochemical etching, an ideal process because it only required one piece of metal and let them control tolerances.

“When creating something that has an overall thickness of under a millimeter, every component and process affects everything else, so you have to consider a lot of variables when working on any part of it,” Vondle explains. “Traditional ways of modularizing components to reduce risk don’t work because more connections means more failure points and thicker assemblies. Also everything needs to be flexible, because at that thickness, making something that cannot withstand flexing is not an option if you want to end up with a robust product. These challenges mean that we have to approach packaging everything in a different way than most electronics.”

To see if the batteries could handle repeated flexing, CST charged the batteries and ran them through bend testing. The Thinergy cells lasted through 4,000 bends from flat to a radius of 22.5 millimeters and held about 85 percent of the initial charge. However, realistically, CST can be confident people aren’t going toput their watch through this much punishment.

CST presented the watches at this year’s Consumer Electronics Show in Las Vegas, generating buzz for its Kickstarter campaign. The company claims the CST-01 is the world’s thinnest watch, and has yet to launch the patent-pending, $129 product. But that hasn’t halted interest. Vondle says there are a few factors that draw people to the design. First, there aren’t many flexible E Ink displays on the market in any product, and certainly none less than 1 millimeter thick.

“When people hold it, many stare at it for up to a minute because they don’t believe it is real and will change,” he says. Plus, because everyone carries mobile phones that keep very accurate time, watches have become perhaps more of a fashion object.

“From the wristwatch side, digital watches haven’t really evolved much in the past years and most of the ones that have have gone the route of complexifying the time. We took the other route.”

With a low profile, high flexibility and hardness, stainless steel may keep more eyes on the time at a slice of the price as, say, a Swiss watch.